1. Field of the Invention
The present invention relates to a grapple of a type having arms that pivot about parallel axes of a frame for grasping and releasing objects and wherein the entire grapple, including the grapple arms, pivots about a pivotal axis transverse to such parallel axes, and more particularly to a grapple which is pivotally adjustable about such pivotal axis between a first position and can be locked in at least the first and second positions thereof. A heel is fixed to the frame for supporting an object being grasped by the grapple when the grapple is in the first pivotal position thereof.
2. Description of Related Art
Grapples with heels are well known, for example in U.S. Pat. No. 2,757,037 to Troyer, which is incorporated herein by reference, U.S. Pat. No. 4,486,136 to Howard and U.S. Pat. No. 6,551,051 to Perron et al. The known configuration, as disclosed in Troyer, Howard and Perron et al., includes a grapple, with two grapple arms that move about a common grapple arm pivot shaft. The grapple arm pivot shaft is supported in a structure that is mounted to a frame at a grapple pivot. A heel is also mounted to the frame. The grapple arm pivot shaft is able to freely move relative to the frame and the heel, due to freedom of motion provided by the grapple pivot. There are times when using this structure that the operator may want to control the orientation of the grapple with respect to the heel, for example to grasp a log with the grapple and then orient the log to a position wherein it will swing upwardly against the heel so that the heel prevents the end of the log adjacent the heel from pivoting upwardly with respect to the grapple. This is exceedingly difficult with the aforementioned prior art grapples which have no way to lock the grapple to prevent it from pivoting about the grapple arm pivot shaft.
Of course there are other times when it is desirable to orient the grapple in a predetermined pivotal position for any number of reasons, such as to use a prime mover having a grapple attached thereto to carry a log through a narrow gate; or, alternatively, to orient the log ninety degrees from such narrow gate orientation so that the center of gravity of the log is as close to the prime mover as possible.
There are other times when it may be desires to permit the grapple to freely pivot about a substantially vertical axis, so the preferred embodiment of the present invention can be used in that mode as well.
Accordingly there is a need for a grapple apparatus to overcome these aforementioned problems with prior art devices.